The present invention relates to an illuminating apparatus illuminating, for example, a transmission-type liquid crystal panel from the backside and a display apparatus having the same.
In recent years, a liquid crystal display apparatus is replacing a CRT (Cathode Ray Tube) as the mainstream of a display apparatus in related art because of its advantages such as low power consumption and smallness, lower price, and the like.
There are some types of liquid crystal display apparatuses when they are classified, for example, by methods of illuminating an image. A representative one is a transmission-type liquid crystal display apparatus displaying an image by using a light source disposed at the back of a liquid crystal panel.
In such a display apparatus, it is demanded to widen a color reproduction range. As one of the methods, it is proposed to use LEDs (Light Emitting Diodes) of three primary colors of blue, green, and red as a light source in place of a CCFL (Cold Cathode Fluorescent Lamp). It is also proposed to use LEDs of not only three primary colors but four or six primary colors in order to widen the color range.
In the case of using a CCFL or LED as the light source, it may be necessary to uniform a brightness distribution and a color distribution in a plane. When an illuminating apparatus is relatively small, a light guide plate of a side light type may be used. In the case where an illuminating apparatus is relatively large and a large light amount is necessary, a direct below type of directly arranging light sources is the mainstream. As one of methods of suppressing brightness unevenness and color unevenness in the direct below type, a method of disposing a diffusion plate, to which a filler is added, above a light source is proposed (Japanese Unexamined Patent Application Publication No. Sho54-155244). As another method, a method of using a plate having a uniform sectional shape in one direction is proposed (Japanese Unexamined Patent Application Publication No. 2005-326819).
In the case of using LEDs of three primary colors as a light source of an illuminating apparatus, as compared with the case of using a CCFL as a light source of an illuminating apparatus, it is difficult to suppress brightness unevenness and color unevenness in a plane for the following reasons. LEDs are point light sources and, while a CCFL generates white light, LEDs of three primary colors have to generate white light by mixing the three colors. For example, the invention of Japanese Unexamined Patent Application Publication No. Sho54-155244) has a problem such that, when LEDs are used as the light source, the distance from the light source to a diffusion plate may be necessary to be relatively long, and the illuminating apparatus becomes thick. On the other hand, the invention of Japanese Unexamined Patent Application Publication No. 2005-326819 has a problem such that, although the CCFL as a linear light source is valid, brightness unevenness and color unevenness occurs in LEDs as the point light sources.
It is therefore desirable to provide an illuminating apparatus realizing reduced brightness unevenness and color unevenness which occurs due to point light sources, and a display apparatus having the same.